Different types of pumps are used within many different technical areas. One particular area where reliable and efficient pumps are essential is in mines or pits where pumps run more or less constantly to drain water from the mine or pits.
Pumps used for pumping water containing for example sand and other particles are exposed to considerable wear from the sand and particles that are flowing through the channels and the different parts in the pump. Pumps designed for these conditions are robust to resist these rough conditions but it is not easy to find resistant sealing that can be arranged between moving parts within the pump for long periods of time without being worn out by sand particles or other particles in the pumped water or fluid.
One commonly used type of sealing is mechanical resilient sealings that are arranged to be in contact with the moving part to seal a gap or space between adjacent parts. However, these seals are destroyed, by overheating, if they run with low, or without, cooling fluid, for example during start up or testing. Consequently, it is difficult to provide the required reliable sealing between different moving parts within the pump to ensure that the pump is working as intended over a long period of time. Especially in the areas of the pump where there is a high pressure involved and the fluid may contain particles of different sizes and material.